The described subject matter relates generally to metal alloys and more specifically to preparation of low sulfur alloys.
Sulfur has always been difficult to remove from many alloys, and can accelerate oxidation, particularly in high temperature environments such as turbine engines. Superalloys are conventionally desulfurized using ceramic based powders including calcium oxide (CaO), magnesium oxide (MgO), or calcium magnesium carbonate (CaMg(CO3)2), known as dolomite. Calcium and magnesium metal also have been used but have well-known handling issues.
Large quantities of these substances are required in order to maintain a desulfurization reaction at very low sulfur concentrations. The resulting ceramic byproducts are high in oxide content, making them difficult to remove, which complicates subsequent solidification, and reduces product quality.